#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int Factorial(int n)
{
	if (n == 1)
	{
		return 1;
	}
	else
	{
		return n * Factorial(n - 1);
	}

}



int main()
{
	int n = 0;

	scanf("%d", &n);

	printf("%d", Factorial(n));


	return 0;
}